Your blood pressure could actually be shrinking your brain, according to new research.
A study published in The Lancet Neurology has found that dementia-free adults who had high blood pressure in their 40s had smaller brains, by overall volume, when they reached their 70s. Brain volume is a common indicator of neurological health and has been studied to help understand the cause of dementia and other forms of cognitive decline among the elderly.
The study, conducted by researchers from University College London, included 502 people from Britain, now aged 69 to 71, who were part of a lifelong study group. The researchers looked at the participants' blood pressure measurements over time, beginning at age 36 and continuing into their 60s. They found that more rapid increases in blood pressure in middle age led to greater changes in brain health, specifically a smaller brain, later in life.
Participants with high blood pressure in their 40s, or a significant increase in blood pressure through their 30s, were also found to be more likely to have blood vessel damage in the brain, increasing the risk of stroke, according to the research, published August 20 and funded by Alzheimer's Research UK.
High blood pressure, particularly among middle-aged people, has long been linked to risk of dementia and other types of cognitive decline, but it's not entirely clear how it works since the "midlife" period, from 40 to 60, has been so broadly defined.
By using a lifelong study group of participants similar in age, this research is the first of its kind to track how blood pressure changes over time can lead to better or worse brain health later on.
Blood pressure could affect brain health beginning as young as 36
The research found greater increases in blood pressure between age 36 to 43 were linked to a smaller brain volume, adjusting for gender and lifestyle factors such as smoking and socioeconomical status.
But the most significant risk of smaller brain volume was found when blood pressure increased between ages 43 and 53, suggesting that this could be a critical time for long-term brain health. And the more rapid increases in blood pressure, the more significant the changes in brain size and increased risk of blood vessel diseases.
In addition to a smaller overall brain size, greater increases in blood pressure during middle age had a smaller hippocampus in their 70s. The hippocampus is an area of the brain associated with memory formation and learning, according to Jonathan Schott, co-author of the study and professor at University College London Queen Square Institute of Neurology.
"The findings suggest that blood pressure even in our 30s could have a knock-on effect on brain health four decades later ... blood pressure monitoring and interventions aimed at maximizing brain health later in life need to be targeted at least by early midlife," he said in a press release.
Many factors influence brain health
The study also tested for levels of a protein called amyloid, associated with Alzheimer's. Although all of the participants had some level it in their brains, researchers didn't find a connection between that and blood pressure levels.
The researchers also acknowledged that genetics could explain the correlation between brain size and high blood pressure.
Although none of the participants showed any cognitive damage, the study is an important step in understanding how blood pressure plays a major role in overall brain health and risk of serious illnesses like dementia among the elderly, said Dr Carol Routledge, Director of Research at Alzheimer's Research UK, in a press release. It also points the way toward how we could potentially address the issue, she explained.
"High blood pressure in midlife is one of the strongest lifestyle risk factors for dementia, and one that is in our control to easily monitor and manage," she said in the release. "Research is already suggesting that more aggressive treatment of high blood pressure in recent years could be improving the brain health of today's older generations."
The American Heart Association has noted that high blood pressure is increasingly a problem, especially in the U.S., but can be managed through lifestyle changes — cutting back on salt, alcohol, exercising regularly, and eating a balanced diet are all strategies the association recommends. A blood pressure reading less than 120/80 is considered normal.
Additional funders of the study included Medical Research Council, Dementias Platform UK, Wellcome Trust, Brain Research UK, Wolfson Foundation, Weston Brain Institute, Avid Radiopharmaceuticals
Read more:
Healthy living may help offset genetic risk of dementia: study
WHO issues first advice on dementia: exercise and don't smoke
Long-term obesity tied to higher dementia risk in healthy older adults
